package com.musclehack.musclehack.images;

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import android.graphics.Bitmap;
import android.util.Log;

public class MemoryCache {

	private static final String TAG = "MemoryCache";
	private Map<String, Bitmap> cache=Collections.synchronizedMap(
			new LinkedHashMap<String, Bitmap>(10,1.5f,true));//Last argument true for LRU ordering
	private long size=0;//current allocated size
	private long limit=1000000;//max memory in bytes
	
	public MemoryCache(){
		//use 25% of available heap size
		setLimit(Runtime.getRuntime().maxMemory()/4);
	}
	
	public void setLimit(long new_limit){
		limit=new_limit;
		Log.i(TAG, "MemoryCache will use up to "+limit/1024./1024.+"MB");
	}

	public Bitmap get(String id){
		try{
			if(!cache.containsKey(id))
				return null;
			//NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78 
			return cache.get(id);
		}catch(NullPointerException ex){
			ex.printStackTrace();
			return null;
		}
	}

	public void put(String id, Bitmap bitmap){
		try{
			if(cache.containsKey(id))
				size-=getSizeInBytes(cache.get(id));
			cache.put(id, bitmap);
			size+=getSizeInBytes(bitmap);
			checkSize();
		}catch(Throwable th){
			th.printStackTrace();
		}
	}
	
	private void checkSize() {
		Log.i(TAG, "cache size="+size+" length="+cache.size());
		if(size>limit){
			Iterator<Entry<String, Bitmap>> iter=cache.entrySet().iterator();//least recently accessed item will be the first one iterated  
			while(iter.hasNext()){
				Entry<String, Bitmap> entry=iter.next();
				size-=getSizeInBytes(entry.getValue());
				iter.remove();
				if(size<=limit)
					break;
			}
			Log.i(TAG, "Clean cache. New size "+cache.size());
		}
	}

	public void clear() {
		try{
			//NullPointerException sometimes happen here http://code.google.com/p/osmdroid/issues/detail?id=78 
			cache.clear();
			size=0;
		}catch(NullPointerException ex){
			ex.printStackTrace();
		}
	}

	long getSizeInBytes(Bitmap bitmap) {
		if(bitmap==null)
			return 0;
		return bitmap.getRowBytes() * bitmap.getHeight();
	}
}